<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
    class Person {
        constructor(name, age) {
            this.name = name;
            this.age = age;
        }
    
        run() {
            console.log(`${this.name} is running.`);
        }
    }
    
    class Teacher extends Person {
        constructor(name, age, addr) {
            super(name, age);
            this.addr = addr;
        }
    }
    
    const t1 = new Teacher("laoda", 35, "what can i say");
    t1.run();
    </script>
</body>
</html>